The present invention relates to a self-adjusting actuation mechanism and, more particularly, to a self-adjusting actuation mechanism for use in a cable actuated system, such as a bicycle caliper brake system.
In typical caliper brake systems for bicycles, a caliper is operated by pulling a cable against a compressive force provided by a sheath surrounding the cable. Relative movement between the cable and the sheath results in movement of the caliper to cause brake pads on the caliper to engage opposing sides of a wheel rim. During repeated use of the brake system, the effectiveness of the system deteriorates as a result of the cable stretching, compression of the sheath and wear of the brake pads. As a consequence, greater movement of the brake actuating lever is required to move the brake pads into contact with the wheel rim.
A common solution to the deterioration resulting from changes in the length of the cable and sheath, as well as from brake pad wear, is the provision of a sheath adjustment at either the brake caliper or the lever whereby the effective length of the sheath is increased. In addition, the attachment point of the cable to the caliper may be adjusted to take up excessive amounts of slack in the cable.
However, the need for performing a brake adjustment is not always readily obvious to the operator of the bicycle in that the deterioration of the brake effectiveness occurs gradually over time such that the operator may become accustomed to compensating for any deficiencies in the braking system.
Accordingly, there is a need for an actuation mechanism for use in a cable actuated system, such as a bicycle caliper brake system, which may be easily adjusted. In addition, there is a need for such an adjustment to be accomplished automatically such that the mechanism is self-adjusting.